Sonos Connect->"Gaterised" Caiman -> B&W MM-1 Line Out vs Variable?

[Kendalbeefcake]

Ok, no housefire. Whilst the variable output produced more volume with the pot all the way around, it didn't help with the crackle at all..

Crackle Doesn't Appear:
- If I plug headphones into the Caiman Headphone AMP
- If I play the same track through the MM-1 USB Line-in direct to the speakers
- If I play the same track through the MM-1 USB Line-in and out via the headphone AMP

Crackle Does appear:
- If I play the track via the Sonos Internal DAC->MM-1 Analogue Line-in
- If I play the track via the Sonos->Caiman Fixed->MM-1 Analogue Line-in
- If I play the track via the Sonos->Caiman Variable->MM-1 Analogue Line-in
- If I play the track via the Sonos->Caiman Variable->MM-1 Analogue Line-in -> MM-1 Headphone Amp


I have tried this with a couple of tracks that are reliably unreliable, and found the same thing..

So this suggests it's not an output problem after all, but something in analogue line-in stage; the power required to drive the cans is tiny, so it can't be that.

The annoying things is apart from the crackle, the Sonos->Caiman->MM-1 sounds Terrific

Having lived with this for a while, I'm fairly sure my speakers are now out of warranty, so that's not really an option open to me.

I'm going to replace the Phono->3.5mm cable to rule it out, but I wouldn't have expected it to be the problem.?? (Edit: Not the cable!)

Otherwise back to the drawing board for me..